I work for a contractor on the CERN site.  I have been treated poorly by CERN personnel and I believe this may violate with the CERN Code of Conduct. To whom should I address myself at CERN in order to obtain clarifications?

The Code of Conduct applies to CERN personnel in their interactions with contractors on the CERN site. In your case, you should address yourself to the relevant CERN contract manager or the Ombuds office.